Leo Sauermann wrote:
[snip]
> *I think about joining DAWG :-)
> *I want real life examples and real live RDF that fits real life use cases.
>
>> Bob: As you noted, storage space explodes.
>
>
> Eric: >Only if implemented naively. Not much extra space is needed if
> reification is implemented by adding an identifier column to the
> statement table.
>
> My email was about RDF/XML as storage space. No statement table. When I
> deploy real live applications, Idon't want to move my customers into
> installing some RDF storage system or cumbersome embedded database.
> RDF/XML should be fine. This is also for compability reasons.
Drifting from the topic a bit perhaps, but using an RDF store for your
persistency does not immediately mean that you have to force the user
to install a DBMS or anything like that. There's several triple stores
that have their own native persistency format and that can just be
bundled with your product as a library, requiring no extra user effort
for installation. Advantages of such a persistent system over 'just'
RDF/XML are:
- more efficient storage and retrieval times (indexes, trees, etc.
vs. XML parsing)
- lower memory footprint
- lower storage footprint (XML is rather verbose, as you may be
aware)
Also, if you want quads you'll have to use a triple store anyway,
since the RDF/XML format itself has no support for it.
> BTW Real life:
> 99% of all this Reification will be used to state things like:
> - When was this triple added to the store? (date)
> - By Whom ? (chown leo)
> - who has access rights (chmod 777) to it?
>
> this is metadata you will see in any store that is shared by one than
> more person (f.e. in a company environment, to use RDF as an
> organisational memory)
You might want to take a look at the OMM extensions to Sesame
(http://www.ontotext.com/omm), which offer precisely such
functionality (although currently only on a DBMS-based store).
> and these will be masses of triples and masses of reification/context.
Then I'd say that using RDF/XML is not even a realistic option, not as
your persistency format, unless you are prepared to stick a lot of RAM
in your machine.
Jeen
--
Jeen Broekstra Aduna BV
Knowledge Engineer Julianaplein 14b, 3817 CS Amersfoort
http://aduna.biz The Netherlands
tel. +31(0)33 46599877 fax. +31(0)33 46599877